Lyon County approves master‑plan change for 505‑acre Monarch data‑center; project moves to PUD stage

Dec 5, 2025

After hours of testimony for and against, the Lyon County Board of Commissioners approved a master‑plan amendment for Copia Power’s proposed 505‑acre ‘Monarch’ data‑center campus, sending the project into the more detailed planned unit‑development (PUD) review. Commissioners and the applicant emphasized traffic, water, battery safety and economic impacts as the next issues to resolve.

The full story

The Lyon County Board of Commissioners voted Dec. 4 to approve a master‑plan amendment that clears the way for Copia Power’s proposed Monarch data‑center on roughly 505 acres in Mason Valley. The approval changes the site designation from agriculture to a ‘specific plan,’ allowing the company to proceed to the PUD (planned unit development) phase, where engineering, environmental reviews and binding mitigation will be evaluated.

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